Blasting is one of the most relevant processes in mining extraction and its main goal is fragmenting rocks, both ores and sterile material, by using explosives. This is done according to established safety regulations, operational procedures and techniques that allow performing all the size-reduction process in a safe and efficient way. In the rock blasting process to fragment the rock, it is necessary to cause contention or confinement of the energy generated by explosives, which cause rock breakage and fragmentation by expanding them. Therefore, the structural strength of the rock has to be surpassed to cause rock displacement.
Currently, mining industry uses soil or ground material or the same cuttings or detritus material (material that remains around each borehole or blast hole due to perforation), which is used as a plug to stem boreholes or blast holes with the aim of confining the explosive charge. Mini-loaders or bobcats are used to stem boreholes or blast holes, and human labor is used when boreholes or blast holes cannot be machine-stemmed, which is the case when equipment cannot access sectors with reduced space. This work is done by using bronze shovels, and the personnel must be careful to select the abovementioned material with no boulders (larger volume rocks), in order to avoid cutting the descending electric lines. Likewise, they have to take into account the safety regulations for said labors. These operational systems are, in short, inefficient and slow, which causes damage in terms of time and a higher operational cost in the system. Likewise, is any borehole or blast hole does not have detritus material to be used for stemming, the operator has to move remnant material from other previously covered boreholes or blast holes, taking the precaution of not damaging electric line in said boreholes or blast holes, by selecting the material and assuring that no larger boulders are present. These actions require more operators and helpers. These personnel must take a stable and safe position, i.e. facing the equipment in such a way as to keep total vision of the operation. Moreover, they must have complete communication with the operator to signal the steps to follow. However, the abovementioned plug material does not serve the purpose of confining the explosive column, because it is completely lose inside the borehole or blast hole and does not oppose the explosive energy once the detonation is activated. As a result, said material, together with the explosive energy, is expelled to the atmosphere, due to a lack of confinement inside the blast hole because it does not have any suitable anchoring system to the borehole or blast hole.
In a blast operation, it is possible to observe that a given percentage of explosive energy is released to the atmosphere. Likewise, the rock fragmentation effectiveness is relative, because the shock waves generated by the explosives have an intensity lower than expected, and so not enough energy propagation is obtained in the blast operation.
A relevant issue in the general extractive industry is related to rock fragmentation, since current techniques do not assure a good fragmentation quality, due to energy losses produced by an inadequate confinement of the gases generated by explosives. Other factors that have a considerable influence in operational and economic terms are, for instance: high explosive, man-hours, and machine-hours requirements, higher wear or lower useful life for machines, equipments and accessories. These reasons make desirable to decrease operational costs and increase the useful life of machines, equipments and accessories.
To optimize the current blasting system, it is desirable to have a stemming apparatus that allows containing or confining the energy generated by explosives and using said energy to fragment rocks, thus allowing other operational technical aspects such as lower costs and productivity increase in great mining.